Apologies for the delay Sean. Re-reading some old threads recently I noticed that I already uploaded a picture of the stone (see image link below) - its the yellow stone on top (top right of image). I now have it in a protective wooden box.

BTW I have 3 of the cheap, flat, cigar-shaped carborundum stones pictured next to it. 2 were my fathers & one I bought. I use them quite a lot for quick, general sharpening. It turns out one is fairly coarse (probably my new one), one is medium and the other is quite fine (& with rounded edges) - presumably due to different degrees of use/wear - quite handy though..